TONER CONCENTRATION CONTROLLER

PURPOSE:To achieve accurate temperature correction and space reduction by providing the toner concentration controller with a temperature detecting element which detects the interior temperature of a developing device near the detecting part of a toner concentration sensor, and which outputs a detected-temperature signal for correcting a temperature for a toner concentration value obtained from the toner concentration sensor. CONSTITUTION:The toner concentration controller is provided with the toner concentration sensor 9 which is fixed to a printed board 8 disposed along the ceiling 7c in a device main body 7 and is electrically connected, and which has the detecting part 9a for detecting the concentration of toner in the developing device. The toner concentration controller is also provided with the temperature detecting element which is fixed to the printed board 8 near the detecting part 9a of the toner concentration sensor 9 in the device main body 7 and is electrically connected, and which detects the interior temperature of the developing device and outputs a detected-temperature signal for correcting the temperature for the toner concentration obtained from the toner concentration sensor 9. Therefore, deviation between the temperature of the detecting part 9a of the toner concentration sensor 9 and the temperature detected by the temperature detecting element 10 is eliminated. Thus, accurate temperature correction and space reduction can be achieved.